The kids are back in school, the tourists are gone -- most of them, anyway -- and we have our Cape back. Time to kick back and relax? Maybe. But as you are preparing your car for the upcoming cold weather, consider doing the same for that electronic box on which so much of our livelihoods depend.

It is unlikely that your computer will need to withstand the ravages of a nor'easter, but it will definitely face other storms -- phishing, spam, spoofing, and the usual assortment of cyberbiological nemeses -- viruses, worms, Trojans and the like. Also, over the past year, most of our software has been a lot less than diligent in removing so-called temporary files used for program installations and setups, and there may be software -- "shelfware" really -- that you have downloaded but no longer need, and perhaps even older versions of software that you use daily. All that extraneous material takes up precious disk space and slows your computer to a crawl.

You will go through a triage process. There are some programs and files that you use daily and are vital to the health and continuation of your business. These, of course, you leave in place. There are other programs and files that may have been important at one time, but for whatever reason are no longer on the front burner and it is unlikely that they will be ever again. You want to lose these. The difficulty arises with a sometimes sizeable group in the middle -- software you use or refer to only rarely, but is vital when you need it. There is a solution to the "I'm not sure" dilemma.

If there are rarely used files and programs you want to save -- the ratty old Teddy bears you just can't part with -- consider investing in an external hard drive. These are plug-and-play USB devices, and for about a hundred bucks or less you will get about 100 GB of disk space. If you fill that up with only memorabilia, your problems are beyond the scope of this column.

But if you want to maximize the performance of the machine you have, here's how to clean up your hard disk and perhaps add a few years to your computer's life.

Cull mercilessly. There are doubtless Word files, Excel spreadsheets, maybe even one-time PowerPoint presentations you will never use again. Delete them along with their associated backups. Many people forget to delete the backups that Office creates and they are surprised at how much space they take up. If you are really concerned about losing truly vital individual files, consider saving them on a flash drive -- a USB-connected device that you can put in your pocket and has up to about four GB of capacity.

Clean up e-mail. Some people have e-mail messages in their Inbox that go back to the Reagan administration. If they are truly vital, move them. If not, lose them. This includes jokes from Cousin Harry, sound bites of little Ethan's first gurgles and pictures of his proud parents. Empty the spam folder if you have one. Also, empty the Deleted file. You may have deleted something, but it may not have gone completely away.

What about downloads?

Here it gets a little tricky.

You may have downloaded some files from zdnet.com -- one of my favorites for good stuff for next to nothing -- that you no longer use. Or you may have downloaded an evaluation version that has expired. Or games that have become borr-rring. Lose them, especially those with sound and graphics.

Downloads from iTunes or other music or video sites present a different problem. You want access, but you don't want to bog down up your hard disk.

The solution is mentioned above: an external hard disk. But the trick here is to keep the iTunes software on your hard disk, but keep your "library" off-site, so to speak. In that way, the program is at your beck and call, but the music is easily accessible -- elsewhere.

After you have done this, here is where the cleanup software comes in. Some of these programs are redundant, and all of them are free for the downloading or bundled with your operating system.

Disk Cleanup. This is one of the system tools that are part of Windows XP. Find it by clicking on Start, then All Programs, then Accessories, then System Tools.

It calculates the area you would free up if you deleted certain files of dubious utility and compressed the rest. It also gives you the opportunity to check each file before deleting it.

Spyware Search and Destroy and AdAware. These programs as the names imply, search for spyware and advertising that may be lurking on your computer to pop up at annoying intervals.

They are available free for the downloading and are updated periodically.

There are other diskcleaning programs, such as CCleaner and EasyCleaner, also free, but Spyware S&D and AdAware are the most widely used. They are not, however, a substitute for a good anti-virus program suite, like those available from Symantec (Norton) and McAfee.

The last step -- after you have removed extraneous programs, files, spyware, adware, malware; after you have moved your old favorites to the external hard disk, after you have emptied the recycle bin -- is to defrag. When you invoke a program, the computer uses it a piece at a time, and when it finishes with a piece, it puts the piece at any convenient location, which is not necessarily where it came from. As a result, the program may become fragmented -- scattered all over the disk.

When you use the program again, the computer will take extra time to find all the pieces. Defragmenting, or defraging, collects all the pieces into a single space on the disk and squeezes out the space between the pieces. Thus, with fewer places to look for pieces, your computer runs faster.

Do this last because it doesn't make sense to optimize the location of files you will eventually delete.

Give Your Computer a New Lease on Life Sure, your number cruncher is getting a little long in the tooth, and it isn't quite the speed demon it was four years ago. Still, if you bought wisely and your computer has a clear upgrade path, you may be able to squeeze some more life out of it. But you have to decide whether upgrading your present machine makes good economic sense; depending on how you use it and what software you intend to run, it may be more cost-effective to start over again.

The easiest upgrade is to add more RAM memory.

Usually you don't just add a chip or two to what you have; most likely, you will upgrade a set of chips.

Most older computers have 512KB of RAM, which is considered barely adequate these days. Load your machine with as much RAM as it will accept. Some of today's screamers are loading 4 GB and more, but going from 512 KB to 2 GB -- increasing capacity four times -- will make a startling improvement. And it is relatively inexpensive as well.

The next improvement to consider is upgrading your hard disk. Four years ago a 40 GB hard disk was considered ample. Today, entry-level computers have hard disks twice that size.

To upgrade, look for a disk that is at least twice as large as what you are using now, consistent with your operating system's capabilities.

If you see two disks with the same capacity but one is significantly more expensive than the other, the more expensive one is probably faster. This can be a major factor when the disk starts to fill up. Finally, consider upgrading to a faster processor.

I listed this last because it is the most expensive and is not always possible. Machines back in the day ran at about 1.0 -- 1.2 GHz.

Today's chips are twice as fast. This is important for gaming, serious graphics and crunching large amounts of data. It is also important for streaming video and other Internet applications. Decide if the first two options will satisfy you before you consider this, because in many cases you can't replace just the chip. The new chip will probably require a new motherboard, and rather than add RAM, upgrade the hard disk and replace the processor and motherboard, it is probably more cost-effective to look for a new computer.

The new models, in addition to being faster, have larger, brighter screens available, as well as a dizzying assortment of bells and whistles that will appease the most ardent gadget freak.

But that's your call.

Stan Elias writes on business technology issues and operates Tensor Communications, a West Barnstable marketing communications agency that specializes in technology-based businesses. He can be reached at 323-401-1290 or TensorComm@ comcast.net.